GET /api/v1/customers/{customer_id}/profile/unified
Authorization: Bearer {access_token}

{
  "customer_id": "cust_123456",
  "profile": {
    "name": "John Doe",
    "email": "john@example.com",
    "phone": "+44123456789"
  },
  "channels": {
    "web": {"last_active": "2024-01-15T10:30:00Z", "sessions": 45},
    "mobile_ios": {"last_active": "2024-01-15T09:15:00Z", "sessions": 120},
    "mobile_android": {"last_active": "2024-01-10T14:00:00Z", "sessions": 30}
  },
  "preferences": {
    "notification_channel": "PUSH",
    "preferred_language": "en"
  }
}

POST /api/v1/sessions/handoff
Content-Type: application/json
Authorization: Bearer {access_token}

{
  "source_session_id": "sess_web_123",
  "target_channel": "MOBILE_IOS",
  "context": {
    "current_flow": "PAYMENT",
    "transaction_draft_id": "draft_abc789"
  }
}

{
  "handoff_token": "ho_xyz123",
  "expires_at": "2024-01-15T10:35:00Z",
  "target_channel": "MOBILE_IOS",
  "context_preserved": true
}

POST /api/v1/sessions/resume
Content-Type: application/json
Authorization: Bearer {access_token}

{
  "handoff_token": "ho_xyz123",
  "channel": "MOBILE_IOS",
  "device_id": "device_abc123"
}

{
  "session_id": "sess_mobile_456",
  "customer_id": "cust_123456",
  "context": {
    "current_flow": "PAYMENT",
    "transaction_draft_id": "draft_abc789"
  },
  "handoff_complete": true
}

GET /api/v1/analytics/channels
Authorization: Bearer {access_token}

{
  "channels": [
    {"channel": "WEB", "active_users": 1200, "transactions": 3500},
    {"channel": "MOBILE_IOS", "active_users": 2500, "transactions": 8200},
    {"channel": "MOBILE_ANDROID", "active_users": 1800, "transactions": 5100},
    {"channel": "API", "active_users": 150, "transactions": 25000}
  ],
  "cross_channel_journeys": 450
}